Maths

Among the examinees in an examination 30%, 35% and 45% failed in Statistics, in Mathematics, and in at least one of the subjects respectively. An examinee is selected at random. Find the probabilities that
a. He failed in Mathematics only
b. He passed in Statistics, if it is known that he has failed in Mathematics

1. 👍 2
2. 👎 1
3. 👁 1,884
1. P(S and M) = P(S) + P(M) - P(S or M)
= .3 + .35 - .45
= .2

You could now make a Venn Diagram with two overlapping circles called S and M
Enter .2 into the overlap ( the P(S and M) )
since S must be .3 and .2 is already accounted for, the part of ONLY S would be .1
in the same way the part of M only would be .15

1. 👍 2
2. 👎 12

Similar Questions

1. Psychology

An essential part of scientific thinking is not only how to use statistics correctly, but also how to identify the misuse of statistics. Our textbook authors suggest that students should: Answer distrust all statistics because

2. Further maths

In an examination 31 candidate passed Chemistry,29 passed Physics 3 failed both subjects.lf 50 candidates sat for the examination how many of them passed Chemistry only.

3. Math

In a group of 105 students, 70 students passed Mathematics, 60 students passed History and 45 students passed Geography; 30 students passed Mathematics and History, 35 students passed History and Geography, 25 passed Mathematics

4. Math

80 boys took the examination in the three subjects: Chinese, English and Mathematics, and none of them failed in all three subjects. It was noted that 8 passed in English only and 10 passed in Mathematics only; 7 passed in

1. mathematical methods for economics

in a class of 300 students,they were given mathematics test in three subjects namely,economics,statistics and mathematics,90 students failed in economics,100 failed in statistics,96 failed in mathematics,60 failed in economics and

2. math

80 boys took the GCE examination in the three subjects geography, English and mathematics and none of them failed all three subjects, it was noted that 8 passed English only and 10 passed mathematics only, 7 passed mathematics and

3. Mathematics

In an examinationâ€š18 candidate passed mathematicsâ€š17 candidates passed physics, 11 candidates passed both subjects and1 candidate failed both subjects find. The number of candidates that passed mathematics only. The number of

4. Mathematics

(a) Ayisha scored 18 marks more than what he did in the previous examination in which he scored 30. Amina scored 30 marks more than she did the previous examination in which she scored 60. Which of the two girls showed less

1. math

A sample of 64 statistics students at a small college had a mean mathematics ACT score of 28 with standard deviation of 4. Estimate the mean mathematics ACT score for all statistics students at college. Give the 95% confidence

2. Math

In an examination, 1/5 of the candidates failed. It is known that 240 candidates passed. How many candidates took the examination

3. Math 157

Can someone please help me. At a quality control checkpoint on a manafacturing assembly line, 10% of the items failed check A, 12% failed check B, and 3% failed both checks A and B. a. If a product failed check A, what is the

4. math

In a 3 hour examination of 350 questions, there are 50 mathematics problems. If twice as much time should be allowed for each problem as for each of the other questions, how many minutes should be spent on the mathematical